# -*- coding: utf-8 -*-

# Define here the models for your spider middleware
#
# See documentation in:
# https://doc.scrapy.org/en/latest/topics/spider-middleware.html
import os
import random

from scrapy import signals

from spider.settings import USER_AGENT_LIST


class SpiderSpiderMiddleware(object):
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the spider middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_spider_input(self, response, spider):
        # Called for each response that goes through the spider
        # middleware and into the spider.

        # Should return None or raise an exception.
        return None

    def process_spider_output(self, response, result, spider):
        # Called with the results returned from the Spider, after
        # it has processed the response.

        # Must return an iterable of Request, dict or Item objects.
        for i in result:
            yield i

    def process_spider_exception(self, response, exception, spider):
        # Called when a spider or process_spider_input() method
        # (from other spider middleware) raises an exception.

        # Should return either None or an iterable of Response, dict
        # or Item objects.
        pass

    def process_start_requests(self, start_requests, spider):
        # Called with the start requests of the spider, and works
        # similarly to the process_spider_output() method, except
        # that it doesn’t have a response associated.

        # Must return only requests (not items).
        for r in start_requests:
            yield r

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)


class SpiderDownloaderMiddleware(object):
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the downloader middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        # Called for each request that goes through the downloader
        # middleware.

        # Must either:
        # - return None: continue processing this request
        # - or return a Response object
        # - or return a Request object
        # - or raise IgnoreRequest: process_exception() methods of
        #   installed downloader middleware will be called
        return None

    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest
        return response

    def process_exception(self, request, exception, spider):
        # Called when a download handler or a process_request()
        # (from other downloader middleware) raises an exception.

        # Must either:
        # - return None: continue processing this exception
        # - return a Response object: stops process_exception() chain
        # - return a Request object: stops process_exception() chain
        pass

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)


class ProxyMiddleware(object):
    """
    设置Proxy
    """
    def __init__(self, ip=''):
        # self.ip = ip
        self.filename = os.path.dirname(os.path.abspath(__file__)) + "\\config\\proxies.txt"
        self.ip = self.get_ip_list()  # 返回的ip列表，包含换行符，调用时需要去'\n'

    def get_ip_list(self):
        with open(self.filename) as f:
            lines = f.readlines()
        return lines

    def process_request(self, request, spider):
        request.meta['proxy'] = 'http://' + random.choice(self.ip).strip()  # 去掉末尾的换行符


class MyUserAgentMiddleware(object):

    def __init__(self, agents):
        self.agents = agents

    @classmethod
    def from_crawler(cls, crawler):
        return cls(crawler.settings.getlist('USER_AGENT_LIST'))

    def process_request(self, request, spider):
        # print "**************************" + random.choice(self.agents)
        request.headers.setdefault('User-Agent', random.choice(self.agents))


class SignalMiddleware(object):
    def __init__(self):
        self.count = 0
        self.record_total = 0

    @classmethod
    def from_crawler(cls, crawler):
        self = cls()

        crawler.signals.connect(self.close_process, signals.spider_closed)
        crawler.signals.connect(self.item_process, signals.item_scraped)

        return self

    def close_process(self):

        print('close')
        # with open('record.txt', 'w') as f:
        #     f.write('close')

    def item_process(self, item):

        # print('spider item')
        self.count = self.count + 1
        self.record_total = item['total']
        print('signal:', self.count, self.record_total)
        print(item)
        percent = int((self.count / self.record_total) * 100)
        print(percent)
        # self.signal.send_percent.emit(percent)
        # 10条记录写一次
        # if self.count:  # % 10 == 0
        #     with open('record.txt', 'w') as f:
        #         f.write(str(percent))
